CLL4756A TR Equivalent & Substitute Parts

Part Overview

The CLL4756A TR is a Zener diode manufactured by Central Semiconductor Corp, rated at 47 V nominal voltage with 1 W maximum power dissipation in a surface mount MELF package (DO-213AB). This component is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design support and procurement.

Zener diodes in this voltage and power class are used for voltage regulation, overvoltage protection, and reference applications in electronic circuits. The obsolete status of the CLL4756A TR requires engineers to select from active alternative components that maintain electrical and mechanical compatibility with the original design.

Key Parameters

Parameter	CLL4756A TR	Unit
Voltage - Zener (Nom)	47	V
Tolerance	±5%	—
Power - Max	1	W
Impedance (Max)	80	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 35.8 V
Voltage - Forward (Vf) (Max) @ If	1.2	V @ 200 mA
Operating Temperature Range	-65°C ~ 200°C	—
Mounting Type	Surface Mount	—
Package / Case	DO-213AB, MELF	—
Moisture Sensitivity Level	1 (Unlimited)	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the CLL4756A TR is determined by the following critical parameters:

Primary Matching Criteria:

Zener voltage: 47 V nominal
Tolerance: ±5% (exact match required for precision applications)
Power rating: 1 W minimum
Package: DO-213AB / MELF surface mount
Mounting type: Surface mount

Secondary Compatibility Factors:

Impedance (Zzt): 80 Ohms maximum
Reverse leakage current: 5 µA @ 35.8 V
Forward voltage: 1.2 V @ 200 mA
Operating temperature range: -65°C to 200°C preferred

Substitute parts are grouped into three categories based on electrical performance:

Category 1: Direct Electrical Equivalents (1 W, ±5% tolerance) Parts with identical power rating and tolerance specifications. These provide the closest functional replacement.

Category 2: Enhanced Performance Substitutes (1.25 W or 1.5 W, ±5% tolerance) Parts with higher power ratings and improved electrical characteristics. These offer superior performance margins and lower impedance.

Category 3: Tolerance Variants (1 W, ±10% or ±20% tolerance) Parts with relaxed tolerance specifications. These are suitable only for applications where voltage tolerance is not critical.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (V)	Tolerance	Power (W)	Zzt (Ohms)	Ir @ Vr (µA)	Vf @ If (V)	Temp Range (°C)	Product Status
CLL4756A TR	Central Semiconductor	47	±5%	1	80	5 @ 35.8	1.2 @ 200 mA	-65 ~ 200	Obsolete
1N4756AUR	Microchip Technology	47	±5%	1	80	5 @ 35.8	1.2 @ 200 mA	-65 ~ 175	Active
1N3036BUR-1	Microchip Technology	47	±5%	1	80	10 @ 35.8	1.2 @ 200 mA	-55 ~ 175	Active
CDLL3036B	Microchip Technology	47	±5%	1	80	0.5 @ 35.8	1.2 @ 200 mA	-55 ~ 175	Active
CDLL3036A	Microchip Technology	47	±10%	1	80	0.5 @ 35.8	1.2 @ 200 mA	-55 ~ 175	Active
CDLL3036	Microchip Technology	47	±20%	1	80	0.5 @ 35.8	1.2 @ 200 mA	-55 ~ 175	Active
CDLL5941B	Microchip Technology	47	±5%	1.25	67	1 @ 35.8	1.2 @ 200 mA	-65 ~ 175	Active
1N5941BUR-1	Microchip Technology	47	±5%	1.25	67	1 @ 35.8	1.2 @ 200 mA	-65 ~ 175	Active
CDLL4481	Microchip Technology	47	±5%	1.5	50	0.05 @ 37.6	1 @ 200 mA	-65 ~ 175	Active
CDLL4756A	Microchip Technology	47	±5%	—	80	0.1 @ 35.8	1.2 @ 200 mA	-65 ~ 175	Active
CDLL4756	Microchip Technology	47	±10%	—	80	0.1 @ 35.8	1.2 @ 200 mA	-65 ~ 175	Active

Engineering Selection Recommendations

Primary Recommendation: 1N4756AUR

The 1N4756AUR from Microchip Technology is the closest functional equivalent to the CLL4756A TR. It matches all critical electrical parameters: 47 V nominal voltage, ±5% tolerance, 1 W power rating, 80 Ohms impedance, and 5 µA reverse leakage current. The operating temperature range is -65°C to 175°C, which covers the majority of industrial and commercial applications. This part is in active production status, ensuring long-term availability and supply chain stability.

Secondary Recommendation: CDLL3036B

The CDLL3036B provides identical electrical specifications to the primary recommendation with superior reverse leakage characteristics (0.5 µA versus 5 µA). This part is suitable for applications requiring lower leakage current performance. Operating temperature range is -55°C to 175°C, which is adequate for most applications except those requiring the full -65°C lower limit.

Enhanced Performance Option: CDLL5941B or 1N5941BUR-1

These 1.25 W rated parts offer improved power handling capability and lower impedance (67 Ohms versus 80 Ohms). They are electrically compatible with the original design and provide additional thermal margin. Operating temperature range extends to -65°C, matching the original specification. These parts are suitable for designs requiring enhanced reliability or operating in higher ambient temperature environments.

High-Performance Option: CDLL4481

The CDLL4481 provides the highest power rating (1.5 W) and lowest impedance (50 Ohms) among available substitutes. Reverse leakage current is significantly reduced to 50 nA. This part is recommended for applications with stringent performance requirements or where thermal management is critical. Operating temperature range is -65°C to 175°C.

Tolerance-Relaxed Options: CDLL3036A (±10%) and CDLL3036 (±20%)

These parts are suitable only for applications where voltage tolerance is not critical to circuit function. The CDLL3036A with ±10% tolerance and CDLL3036 with ±20% tolerance offer cost advantages but should not be used in precision voltage regulation or reference circuits.

All recommended substitutes are manufactured by Microchip Technology and are in active production status, ensuring availability and supply chain continuity.

Frequently Asked Questions (FAQ)

Q1: Can I use 1N4756AUR as a direct replacement for CLL4756A TR?

Yes. The 1N4756AUR is electrically and mechanically compatible with the CLL4756A TR. Both components have identical nominal voltage (47 V), tolerance (±5%), power rating (1 W), impedance (80 Ohms), and package type (DO-213AB MELF). The operating temperature range of the 1N4756AUR (-65°C to 175°C) covers the majority of applications, though it does not extend to the original part's upper limit of 200°C.

Q2: What is the difference between the CDLL5941B and 1N5941BUR-1?

Both parts are electrically identical: 47 V nominal voltage, ±5% tolerance, 1.25 W power rating, 67 Ohms impedance, and -65°C to 175°C operating range. The difference is in manufacturer designation and packaging format. Both are manufactured by Microchip Technology and are suitable substitutes for applications requiring enhanced power handling.

Q3: Why should I choose CDLL4481 over 1N4756AUR?

The CDLL4481 offers superior electrical performance: higher power rating (1.5 W versus 1 W), lower impedance (50 Ohms versus 80 Ohms), and significantly lower reverse leakage current (50 nA versus 5 µA). Select CDLL4481 for applications requiring enhanced thermal margin, lower leakage characteristics, or improved voltage regulation performance. The trade-off is a slightly lower forward voltage (1 V versus 1.2 V at 200 mA).

Q4: Can I use CDLL3036 (±20% tolerance) in my circuit?

CDLL3036 is suitable only for applications where the ±20% voltage tolerance does not affect circuit function. Do not use this part in precision voltage regulation, reference circuits, or overvoltage protection applications where voltage accuracy is critical. For these applications, select parts with ±5% tolerance such as 1N4756AUR or CDLL3036B.

Q5: What is the impact of operating temperature range differences?

The CLL4756A TR operates from -65°C to 200°C. Most active substitutes operate from -65°C to 175°C, which is adequate for industrial and commercial applications. If your circuit requires operation above 175°C, verify that the substitute part's thermal characteristics are suitable for your specific application. The 1N4756AUR and CDLL5941B maintain the -65°C lower limit, ensuring compatibility with low-temperature applications.

Q6: Are all substitute parts in the same package?

Yes. All recommended substitute parts use the DO-213AB MELF surface mount package, which is mechanically and electrically compatible with the original CLL4756A TR. No PCB layout modifications are required for substitution.

Q7: What does "Active" product status mean?

Active status indicates that the part is currently in production and available from the manufacturer. This ensures long-term supply chain stability and availability for procurement. The CLL4756A TR is classified as obsolete, meaning it is no longer manufactured and existing inventory is limited.

Q8: Should I select a higher power-rated substitute for reliability?

Higher power-rated substitutes (1.25 W or 1.5 W) provide additional thermal margin and can improve circuit reliability in high-ambient-temperature environments. However, they are not required for direct replacement if the original 1 W rating is adequate for your application. Select enhanced power ratings only if thermal analysis indicates benefit or if the application requires improved performance margins.

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